To secret a page

To ensure that the information on a page is kept secret, the following steps should be performed.

To begin with, the ink with which the page is written should be imbued with either residium, or magical ointments. If this is not available and the information is already
written on the page, then further steps should be taken to invest magical energy in the shape of the letters into the page itself. Once this is complete, magical energy should be used to remove the ink from the page, and store it within an extra dimensional pocket in the page. This can often be disguised as a full stop, or other punctuation mark.

This completed, the ink can be retrieved at will, although it will remain visible to its creators, and those who they alert to its presence. To others it should simply seem to be residual magical energy to any who examine it, common amongst wizards, as a book that was too often manipulated by a magical hand.